Frame tube



FIG. 1 is a right-front perspective view showing the design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is bottom view thereof; and,

FIG. 8 is right-rear perspective view thereof.

The broken lines illustrate environmental structure and form no part of the claimed design. 

The ornamental design for a frame tube, as shown and described. 